The qwerty keyboard has become a worldwide standard for alpha-numeric data entry, but as electronic functionality is increasingly miniaturized, the size of a usable touch-typing keyboard becomes much larger than the package needed for many modern devices. Thus, there is an increasing need for a widely acceptable method for entering alpha-numeric data that can be easily incorporated into small handheld devices.
One proposed solution to this problem has been to miniaturize the keys of the querty keyboard and other controls. At same time, since the development of the push-button telephone, attempts have been made to find a widely acceptable method for alpha-numeric data entry using the pushbutton telephone as a remote data terminal. U.S. Pat. No. 3,675,513 purports to describe a method of alpha-numeric data entry from the telephone keypad. In accordance with the '513 patent, a plurality of letters are printed on the standard telephone keys and a letter is entered by pressing its corresponding key a predetermined number of times. For example., the "2" key has "ABC" printed on it, and, to form the letter "B", the "2" key is pressed twice to indicate that the desired letter is "3", the second of the three letters printed on the key. Special combinations have been developed to represent "Q" and "Z," which are not printed on the telephone keypad.
U.S. Pat. No. 5,559,512 purports to use "hard keys" which represent a plurality of characters in combination with "soft keys" displayed on a screen which are used to select the correct one of several possible hard key characters.
Another proposed system is to use chorded keypads in which combinations of keys are pressed simultaneously. One example of such a system is the Stenotype machine used in court reporting. Variations on this system have also been proposed. For example, U.S. Pat. Nos. 4,360,892 and 4,443,789 purport to provide a 5-key chorded system designated "Microwriting", which utilizes a special apparatus having four finger keys and at least one thumb key, and in which the pre-selected key combinations were chosen to suggest a pictographic relationship to the English alphabet.
Finally, the availability of powerful computers in small packages has given rise to systems that bypass the use of keys entirely, including, for example, voice recognition software which is responsive to spoken words, and handwriting recognition software which is responsive to a special stylus and touch screen.